Silicon nanoparticles of ˜1 nm diameter have shown stimulated emissions. See, Nayfeh et al. U.S. Pat. No. 6,585,947, entitled METHOD FOR PRODUCING SILICON NANOPARTICLES; Nayfeh et al. U.S. Published Patent Application, as publication number 20020070121, published on Jul. 13, 2002 and entitled FAMILY OF DISCRETELY SIZED NANOPARTICLES AND METHOD FOR PRODUCING THE SAME. Bulk silicon is an optically dull indirect bandgap material, having a 1.1 eV indirect bandgap, a 3.2 eV direct bandgap. A 1 nm silicon nanoparticle effectively creates a new wideband direct gap material, with an energy gap of 3.55 eV, and highly efficient optical activity. A 1 nm silicon nanoparticle indirect band gap of 1.1 eV corresponds to a wavelength of 1.1 μm, which is in the infrared region. Uniformly dimensioned 1 nm silicon nanoparticles (having about 1 part in one thousand or less of greater dimensions) have characteristic blue emissions. See, e.g., Akcakir et al, “Detection of luminescent single ultrasmall silicon nanoparticles using fluctuation correlation spectroscopy”, Appl. Phys. Lett. 76 (14), p. 1857 (Apr. 3, 2000). The silicon nanoparticles have also been synthesized with H- or O-termination, or functionalized with N-, or C-linkages.
In addition to the 1 nm silicon nanoparticle material, previous work has also produced a family of uniformly dimensioned nanoparticles with distinct particle sizes in the 1-3 nm range, which fluoresce spectacularly, and an additional particle that emits in the infrared band. The family includes 1 (blue emitting), 1.67 (green emitting), 2.15 (yellow emitting), 2.9 (red emitting) and 3.7 nm (infrared emitting). See, G. Belomoin et al. “Observation of a magic discrete family of ultrabright Si nanoparticles,” Appl. Phys. Lett. 80(5), p 841 (Feb. 4, 2002); and United States Published Patent Application 20020070121 to Nayfeh et al.
A plating process for plating films of silicon nanoparticles is disclosed in U.S. Pat. No. 6,660,152 to Nayfeh et al, entitled ELEMENTAL SILICON NANOPARTICLE PLATING AND METHOD FOR THE SAME. In that process, silicon nanoparticles are plated in an electrolytic cell to a substrate, which is the anode of the cell when plating silicon nanoparticles and can be the cathode for composite deposits including silicon nanoparticles. Particles deposit at a solution-air interface and form a plating.